package com.himalayan.bear.util;

import java.net.InetAddress;
import java.util.UUID;

/**
 * uuid工具类
 * Created by charlin on 2017/9/9.
 */
public class UUIDUtil {
    private String sep = "";
    private static int IP = 0;
    private static short counter = (short) 0;
    private static int JVM = (int) (System.currentTimeMillis() >>> 8);

    static {
        try {
            IP = toInt(InetAddress.getLocalHost().getAddress());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static UUIDUtil instance = new UUIDUtil();

    public static UUIDUtil getInstance() {
        return instance;
    }

    public static UUIDUtil getInstance(String sep) {
        instance.sep = sep;
        return instance;
    }

    public static void setSep(String sep) {
        instance.sep = sep;
    }

    /**
     * byte转int
     *
     * @param bytes
     * @return
     */
    public static int toInt(byte[] bytes) {
        int result = 0;
        for (int i = 0; i < 4; i++) {
            result = (result << 8) - Byte.MIN_VALUE + (int) bytes[i];
        }
        return result;
    }

    protected String format(int intval) {
        String formatted = Integer.toHexString(intval);
        StringBuilder buf = new StringBuilder("00000000");
        buf.replace(8 - formatted.length(), 8, formatted);
        return buf.toString();
    }

    protected String format(short shortval) {
        String formatted = Integer.toHexString(shortval);
        StringBuffer buf = new StringBuffer("0000");
        buf.replace(4 - formatted.length(), 4, formatted);
        return buf.toString();
    }

    protected int getJVM() {
        return JVM;
    }

    protected synchronized short getCount() {
        if (counter < 0) {
            counter = 0;
        }
        return counter++;
    }

    protected int getIP() {
        return IP;
    }

    protected short getHiTime() {
        return (short) (System.currentTimeMillis() >>> 32);
    }

    protected int getLoTime() {
        return (int) System.currentTimeMillis();
    }

    public String generate() {
        return format(getIP()) + sep +
                format(getJVM()) + sep + format(getHiTime()) +
                sep + format(getLoTime()) + sep +
                format(getCount());
    }

    // 得到一个序号
    public static String getUUID() {
        String uuid = UUID.randomUUID().toString();
        return uuid.replace("-", "");
    }

    /**
     * 一次得到多个序号
     *
     * @param number int 需要获得的序号数量
     * @return String[] 序号数组
     */
    public static String[] getUUID(int number) {
        if (number < 1) {
            return null;
        }
        String[] ss = new String[number];
        for (int i = 0; i < ss.length; i++) {
            ss[i] = getUUID();
        }
        return ss;
    }
}